Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

Alexander Gordeev
2013-10-08T07:33:02Z

On Tue, Oct 08, 2013 at 03:33:30PM +1100, Michael Ellerman wrote:
> On Wed, Oct 02, 2013 at 12:29:04PM +0200, Alexander Gordeev wrote:
> > This technique proved to be confusing and error-prone. Vast share
> > of device drivers simply fail to follow the described guidelines.
>
> To clarify "Vast share of device drivers":
>
> - 58 drivers call pci_enable_msix()
> - 24 try a single allocation and then fallback to MSI/LSI
> - 19 use the loop style allocation as above
> - 14 try an allocation, and if it fails retry once
> - 1 incorrectly continues when pci_enable_msix() returns > 0
>
> So 33 drivers (> 50%) successfully make use of the "confusing and
> error-prone" return value.

Ok, you caught me - 'vast share' is incorrect and is a subject to
rewording. But out of 19/58 how many drivers tested fallbacks on the
real hardware? IOW, which drivers are affected by the pSeries quota?

> And yes, one is buggy, so obviously the interface is too complex. Thanks
> drivers/ntb/ntb_hw.c

vmxnet3 would be the best example.

> cheers

--
Regards,
Alexander Gordeev
agordeev@redhat.com